Cooler

ABSTRACT

A cooler is provided with a thermal transmission member having a surface to be sprayed with a cooling fluid. The heat transmission member includes a first groove formed on the surface, and a second groove intersecting with the first groove and being formed on the surface.

TECHNICAL FIELD

The present invention relates to a cooler.

BACKGROUND ART

In addition to a cooler for performing a heat exchange by carrying a cooling fluid to the inside so as to cool an object to be cooled arranged on a surface of the cooler, there is another cooler where the object to be cooled is arranged in a thermal transmission member and cooling is performed by spraying the cooling fluid towards the thermal transmission member.

Japanese Patent Laying-Open No. 3-30457 discloses a cooling method of a semiconductor device for supplying and vaporizing predetermined liquid in a heat generating unit of the semiconductor device so as to cool the heat generating unit by latent heat in vaporization thereof. According to this cooling method of the semiconductor device, it is possible to improve cooling efficiency and reliability of the semiconductor device, to simplify and downsize a cooling structure, and to prevent corrosion and contamination due to the cooling fluid.

Japanese Patent National Publication No. 2001-521138 discloses a device for performing two-phase cooling with regard to a cooling device for an electronic element. This two-phase cooling device has a first housing unit, a second housing unit and a third housing unit. One or more spraying nozzle is fixed to an inner surface of the second housing unit, and further, one or more electronic element with high power is installed at a position facing the spraying nozzle on an outer surface. In the second housing unit, cooling liquid is sprayed from the spraying nozzle by a pump. When the cooling liquid is brought in contact with a heating part of the second housing unit, a part of the cooling liquid is converted into vapor and the remaining part of the cooling liquid is returned to the first housing unit in a liquid state.

Japanese Patent Laying-Open No. 2005-86204 discloses a spray cooling system where a main body including a sealed spraying chamber and a thermal transmission wall having an inside surface serving as a border of the thermal transmission wall is provided in a system for cooling a component with a sprayed cooling fluid. In this spray cooling system, an outside surface of the thermal transmission wall is retained relative to a part of the component. A spray is arranged to spray the cooling fluid to the inside surface. It is possible to efficiently install this spray cooling system in a plurality of places within a complicated system.

In the cooler for spraying the cooling fluid, the cooling can be mainly performed by the latent heat in vaporization at the time of vaporizing the cooling fluid. Alternatively, the object to be cooled is cooled by carrying the cooling fluid while taking heat off at the time of spraying the cooling fluid towards the thermal transmission member.

In order to uniformly cool the object to be cooled, at least an area of the thermal transmission member where the object to be cooled is arranged is preferably uniformly cooled. In order to evenly cool the thermal transmission member, the cooling fluid is preferably evenly arranged on a surface of the thermal transmission member.

In a spray cooling module disclosed in Japanese Patent Laying-Open No. 2005-86204 mentioned above, the spray is controlled by a controller and the cooling is performed while spraying by the precise amount. However, in this published patent literature, there is no examination on uniformization of drops on the surface of the thermal transmission wall to be sprayed with the cooling fluid. That is, there is not examination on an action of the cooling fluid after sprayed to the thermal transmission member even when the spraying amount is controlled. There is a problem that unless a state of the drops on the surface of the thermal transmission member is uniform after spraying the cooling fluid, it is not possible to uniformly cool the object to be cooled.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a cooler capable of performing uniform cooling.

A cooler based on the present invention includes a thermal transmission member having a surface to be sprayed with a cooling fluid. The thermal transmission member includes a first channel formed on the surface, and a second channel intersecting with the first channel, the second channel being formed on the surface.

Preferably in the above invention, the first channel is formed to supply the cooling fluid to a substantially entire part of the surface. The first channel is formed to discharge an excessive amount of the cooling fluid. The second channel is formed to facilitate evaporation of the cooling fluid.

Preferably in the above invention, in the second channel, a section perpendicular to an extending direction of the second channel is formed into a stepwise shape.

Preferably in the above invention, in the thermal transmission member, the surface is formed into a convex surface so that a height is gradually reduced from a center part to an outer peripheral part.

Preferably in the above invention, in the thermal transmission member, the surface is inclined so that a height is gradually reduced from a center part to an outer peripheral part.

Preferably in the above invention, each of the first channel and the second channel is formed into a groove shape. At least one channel of the first channel and the second channel is formed to be gradually deepened from a center part to an outer peripheral part of the surface.

Preferably in the above invention, the second channel is formed into a groove shape. The second channel is formed so that at least a part of the second channel generates a capillary phenomenon.

Preferably in the above invention, each of the first channel and the second channel is formed into a groove shape so that the first and second channels have bottom surfaces respectively. The bottom surface of the second channel is formed to be lower than the bottom surface of the first channel.

According to the present invention, it is possible to provide the cooler capable of performing the uniform cooling.

It should be noted that two or more configurations among the configurations described above may be properly combined. That is, proper selection and combination of a part or the entire configurations described above is obviously taken into consideration.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of a cooler in a first embodiment.

FIG. 2 is a schematic plan view of a thermal transmission member in the first embodiment.

FIG. 3 is a first schematic sectional view of a first groove of the thermal transmission member in the first embodiment.

FIG. 4 is a first schematic sectional view of a second groove of the thermal transmission member in the first embodiment.

FIG. 5 is a second schematic sectional view of the first groove of the thermal transmission member in the first embodiment.

FIG. 6 is a second schematic sectional view of the second groove of the thermal transmission member in the first embodiment.

FIG. 7 is a schematic sectional view of another second groove in the first embodiment.

FIG. 8 is a schematic sectional view of further another second groove in the first embodiment.

FIG. 9 is a schematic plan view of a thermal transmission member in a second embodiment.

FIG. 10 is a schematic side view of a first cooler in a third embodiment.

FIG. 11 is a schematic sectional view of a second cooler in the third embodiment.

FIG. 12 is a schematic plan view of a thermal transmission member in a fourth embodiment.

FIG. 13 is a schematic sectional view of the thermal transmission member in the fourth embodiment.

BEST MODES FOR CARRYING OUT THE INVENTION First Embodiment

With reference to FIGS. 1 to 8, a cooler in a first embodiment based on the present invention will be described.

FIG. 1 is a schematic side view of the cooler in the present embodiment. The cooler in the present embodiment is a cooler where cooling is performed by spraying a cooling fluid. The cooler in the present embodiment is provided with a thermal transmission member 1. Thermal transmission member 1 is formed into a plate shape.

A heat generating body 12 serving as an object to be cooled is arranged on a surface of thermal transmission member 1. Heat generating body 12 is connected to a main surface of thermal transmission member 1. In the present embodiment, heat generating body 12 is arranged in a center part of the main surface of thermal transmission member 1.

The cooler in the present embodiment is provided with a spray 11. Spray 11 is arranged to face a main surface of thermal transmission member 1 on the opposite side of the main surface where heat generating body 12 is arranged. Spray 11 is arranged apart from thermal transmission member 1. Spray 11 is formed to spray a cooling fluid 21. That is, spray 11 is formed to jet cooling fluid 21 in a drop shape. Spray 11 is formed to spray cooling fluid 21 towards the main surface of thermal transmission member 1 on the opposite side of the main surface where heat generating body 12 is arranged. In the present embodiment, liquid is used as the cooling fluid.

FIG. 2 shows a schematic plan view of the thermal transmission member in the present embodiment. Thermal transmission member 1 in the present embodiment is formed to have a plan in a substantially circular shape. Thermal transmission member 1 has a first groove 1 a serving as a first channel formed on the surface. Thermal transmission member 1 has a second groove 1 b serving as a second channel intersecting with first groove 1 a and being formed on the surface.

First groove 1 a and second groove 1 b in the present embodiment are formed so that extending directions thereof intersect with each other. First groove 1 a communicates with second groove 1 b. Heat generating body 12 is arranged in an area corresponding to a substantially center part of an area where first groove 1 a and second groove 1 b are formed.

In the present embodiment, there are formed a plurality of first grooves 1 a. First groove 1 a is formed in a substantially entire part of the surface of thermal transmission member 1. First groove 1 a is formed in a linear shape. First groove 1 a is formed to have a clearance between first grooves 1 a. First groove 1 a in the present embodiment is formed at an equal interval. First groove 1 a is formed so that extending directions of first grooves 1 a are parallel to each other. First groove 1 a is formed to extend from one end surface of thermal transmission member 1 to the other end surface. First groove 1 a is formed to discharge an excessive amount of the supplied cooling fluid to the outside of thermal transmission member 1.

In the present embodiment, there are formed a plurality of second grooves 1 b. Second groove 1 b is formed in a linear shape. Second groove 1 b is formed to have a clearance between second grooves 1 b. Second groove 1 b in the present embodiment is formed at an equal interval. Second groove 1 b is formed so that extending directions of second grooves 1 b are parallel to each other. Second groove 1 b is formed so that lengths of second grooves 1 b in the extending directions are substantially the same as each other.

Ends of second groove 1 b are arranged in an area inside the main surface of thermal transmission member 1. Second groove 1 b is formed so as not to reach the end surfaces of thermal transmission member 1. Second groove 1 b is formed so as not to discharge the cooling fluid to be supplied to the inside from the ends of second groove 1 b.

FIG. 3 shows a schematic sectional view of a part of the first groove of the thermal transmission member in the present embodiment. FIG. 3 is an arrow sectional view by the line III-III in FIG. 2. First groove 1 a is formed to pass through from one end surface of thermal transmission member 1 to the other end surface. First groove 1 a is formed so that depth is constant along the extending directions.

FIG. 4 shows a schematic sectional view of a part of the second groove of the thermal transmission member in the present embodiment. FIG. 4 is an arrow sectional view by the line IV-IV in FIG. 2. Second groove 1 b is formed so that depth is constant along the extending direction. Second groove 1 b in the present embodiment is formed so that both the ends do not communicate with the outside.

With reference to FIGS. 3 and 4, thermal transmission member 1 in the present embodiment is formed so that thickness is constant in the extending direction of first groove 1 a and the extending direction of second groove 1 b. The grooves are formed so that bottom surfaces thereof are positioned at a constant height.

FIG. 5 shows an enlarged schematic sectional view of the first groove in the present embodiment. FIG. 5 is a schematic sectional view at the time of cutting in the extending direction of the first groove by a perpendicular surface. First groove 1 a in the present embodiment is formed to have a section in a U-letter shape. First groove 1 a has a bottom surface 9 a. First groove 1 a has depth d1.

FIG. 6 shows an enlarged schematic sectional view of the second groove in the present embodiment. FIG. 6 is a schematic sectional view at the time of cutting in the extending direction of the second groove by a perpendicular surface. Second groove 1 b in the present embodiment is formed to have a section in a stepwise shape. Second groove 1 b is formed to have a plurality of differences. Second groove 1 b is formed so that a center part in the width direction is the deepest. Second groove 2 b has a bottom surface 9 b. Second groove 1 b has depth d2.

Depth d2 of second groove 1 b in the present embodiment is formed to be larger than depth d1 of first groove 1 a. That is, bottom surface 9 b of second groove 1 b is formed to be at a lower position than bottom surface 9 a of first groove 1 a.

With reference to FIG. 1, in a case where cooling of heat generating body 12 is performed, cooling fluid 21 is sprayed from spray 11 towards thermal transmission member 1. In the present embodiment, cooling fluid 21 is sprayed over a substantially entire part of the main surface of thermal transmission member 1 around a center part of a circle in a plan of thermal transmission member 1.

With reference to FIG. 2, in a case where an excessive amount of cooling fluid 21 is sprayed towards thermal transmission member 1, the excessive amount of cooling fluid 21 is discharged from ends of first groove 1 a to the outside of thermal transmission member 1 as shown by an arrow 31. In a case where the excessive amount of the cooling fluid is supplied to second groove 1 b, the excessive amount of cooling fluid 21 is carried from second groove 1 b to first groove 1 a and then discharged.

In a case where the cooling fluid is locally in short, the cooling fluid is carried through first groove 1 a and second groove 1 b and into a shortage point. Therefore, it is possible to substantially uniformly supply the cooling fluid. For example, even in a case where even spraying is not performed from spray 11 towards thermal transmission member 1 due to a transient change and the spraying is disproportionately performed over an area, it is possible to substantially uniformly distribute the cooling fluid through first groove 1 a and second groove 1 b and substantially uniformly cool the thermal transmission member.

In such a way, the cooler in the present embodiment is provided with the thermal transmission member. The thermal transmission member includes the first channel formed on the surface to be sprayed with the cooling fluid and the second channel intersecting with the first channel. By this configuration, it is possible to substantially uniformly arrange the cooling fluid over the entire area where the first groove and the second groove are formed. The thermal transmission member is substantially uniformly cooled in the area where the first groove and the second groove are formed. As a result, it is possible to substantially uniformly cool a member to be cooled.

With reference to FIG. 6, second groove 1 b in the present embodiment is formed to have a section in a stepwise shape and hence a part serving as a difference is formed. Alternatively, a part serving as an edge is formed in the section. By this configuration, cooling fluid 21 is easily accumulated on a surface of second groove 1 b. Since cooling fluid 21 is accumulated, shortage of drops in the second groove can be suppressed and evaporation of the cooling fluid is facilitated.

In the present embodiment, the first groove is formed to supply the cooling fluid to a substantially entire part of the surface of the thermal transmission member and further to discharge an excessive amount of the cooling fluid. Meanwhile, second groove 1 b is formed to facilitate the evaporation of the cooling fluid. By this configuration, the first channel is a channel for mainly supplying the cooling fluid over the entire groove and the second channel is a channel for mainly performing the evaporation. In such a way, it is possible to divide into a plurality of channels having functions respectively and to reduce a change in a cooling performance when the spraying amount is changed.

With reference to FIGS. 5 and 6, in the present embodiment, depth d2 of second groove 1 b is formed to be deeper than depth d1 of first groove 1 a. By this configuration, the cooling fluid carried into first groove 1 a can be easily distributed to second groove 1 b. It is possible to accumulate the cooling fluid in a bottom part of second groove 1 b at even depth and to reduce the change in the cooling performance.

FIG. 7 shows a schematic sectional view of another second groove in the present embodiment. Another second groove 1 c is formed to have a section in a substantially U-letter shape. There are formed a plurality of concave portions 7 on an inner surface of second groove 1 c. Concave portions 7 are formed to have a clearance between concave portions 7.

FIG. 8 shows a schematic sectional view of further another second groove in the present embodiment. Further another second groove 1 d is formed to have a section in a substantially U-letter shape. There are formed a plurality of convex portions 8 on an inner surface of second groove 1 d. Convex portions 8 are formed to have a clearance between convex portions 8.

As shown in FIGS. 7 and 8, since the convex portions or the concave portions are formed on the surface of the second channel, it is possible to form a part serving as an edge in the section of the second groove and to retain the cooling fluid in the second groove. Alternatively, it is possible to increase a surface area of the second groove and to facilitate the evaporation.

A structure of facilitating the evaporation of the second groove is not limited to any of these structures above. For example, a porous material may be arranged on the surface of the second groove. Alternatively, as the structure of facilitating the evaporation of the second groove, a part serving as an edge or a part serving as a difference may be formed in the section as mentioned above. A whisker may be charged in the second groove.

The second groove may be formed so that at least a part thereof generates a capillary phenomenon. By this configuration, the cooling fluid is moved along the second groove due to the capillary phenomenon and it is possible to arrange the cooling fluid over a substantially entire part of the second groove. For example, width of the second groove may be formed to be small enough to generate the capillary phenomenon.

The ends of the second groove in the present embodiment are arranged inside the main surface of the thermal transmission member. However, the present embodiment is not limited to this mode but the ends of the second groove may be formed to reach the end surfaces of the thermal transmission member. By this configuration, it is possible to directly discharge an excessive amount of the cooling fluid supplied to the second groove without carrying through the first groove.

The first groove and a part of the second groove in the present embodiment are formed to have a section in a U-letter shape. However, the present embodiment is not limited to this mode but the section may be formed in an arbitrary shape. For example, the section may be formed in a V-letter shape.

The thermal transmission member in the present embodiment is formed in a plate shape. However, the present embodiment is not limited to this mode but the thermal transmission member may be formed into an arbitrary shape. For example, the thermal transmission member is not limited to a plate shape but may be formed in a rectangular parallelepiped. The thermal transmission member is not limited to one material but preferably formed by a material excellent in thermal conduction.

In the present embodiment, the object to be cooled is arranged on the surface of the thermal transmission member. However, the present embodiment is not limited to this mode but the thermal transmission member may be formed as a part of the object to be cooled. For example, the first channel and the second channel may be formed on a surface of a casing of the object to be cooled and the cooling fluid may be sprayed towards this surface.

The cooler in the present invention can be applied to a cooler for performing the cooling of an arbitrary object to be cooled.

Second Embodiment

With reference to FIG. 9, a cooler in a second embodiment based on the present invention will be described. The cooler in the present embodiment is different from the first embodiment in terms of configuration of the first channel and the second channel of the thermal transmission member.

FIG. 9 is a schematic plan view of the thermal transmission member in the present embodiment. A thermal transmission member 2 is formed in a plate shape. Thermal transmission member 2 is formed to have a plan in a substantially circular shape.

Thermal transmission member 2 in the present embodiment has a first groove 2 a serving as the first channel and a second groove 2 b serving as the second channel. First groove 2 a and second groove 2 b are formed on a surface to be sprayed with the cooling fluid. First groove 2 a and second groove 2 b are formed to intersect with each other. First groove 2 a communicates with second groove 2 b.

Heat generating body 12 serving as the object to be cooled in the present embodiment is arranged on a main surface on the opposite side of the main surface where first groove 2 a and second groove 2 b are formed. Heat generating body 12 is arranged in a substantially center part of an area corresponding an area where first groove 2 a and second groove 2 b are formed.

There are formed a plurality of first grooves 2 a. First groove 2 a is formed in a linear shape. First groove 2 a is formed so that extending directions of first grooves 2 a are formed into a radial shape. First groove 2 a is formed to extend from a center of a circle in the plan of thermal transmission member 2 to an outer periphery. An outside end of first groove 2 a reaches an end surface of thermal transmission member 2. First groove 2 a is formed to discharge an excessive amount of the cooling fluid to the outside.

There are formed a plurality of second grooves 2 b. Second groove 2 b is formed to extend in a substantially circular shape in planar view. Second groove 2 b has a closed shape in planar view. There are formed a plurality of second grooves 2 b in a concentric shape in planar view. Second groove 2 b is formed at an equal interval. Second groove 2 b is formed so as not to reach the end surface of thermal transmission member 2.

Even in the cooler in the present embodiment, it is possible to substantially uniformly arrange the cooling fluid in the area where the first groove and the second groove of the thermal transmission member are formed and to substantially uniformly cool the object to be cooled.

The other configurations, an operation and an effect are the same as the first embodiment and a description thereof will not be repeated.

Third Embodiment

With reference to FIGS. 10 and 11, a cooler in a third embodiment based on the present invention will be described. In the present embodiment, a shape of the thermal transmission member is different from the first embodiment.

FIG. 10 is a schematic side view of a first cooler in the present embodiment. The first cooler in the present embodiment is provided with a thermal transmission member 3. In thermal transmission member 3, a surface where the first groove and the second groove are formed is formed into a convex surface. Thermal transmission member 3 is formed to have a plan in a substantially circular shape.

Thermal transmission member 3 is formed so that a height of a surface to be sprayed with cooling fluid 21 is gradually lowered from a center part towards an outer peripheral. The surface of thermal transmission member 3 is inclined. Thermal transmission member 3 is formed so that a part facing spray 11 is the thickest and thermal transmission member 3 is gradually thinning towards an outer periphery. Thermal transmission member 3 is also formed so that the center part is the thickest and thermal transmission member 3 is gradually thinning towards the outer peripheral part even in the direction along the second groove. Spray 11 is arranged right above the center part of thermal transmission member 3.

A first groove 3 a is formed along the surface facing spray 11. First groove 3 a is formed so that depth is constant. First groove 3 a is formed to reach end surfaces of thermal transmission member 3. A second groove (not shown) is formed so that depth is constant and further so as to reach the end surfaces of thermal transmission member 3.

In the first cooler in the present embodiment, cooling fluid 21 sprayed from spray 11 is carried towards the outer peripheral part in first groove 3 a as shown by an arrow 32. Since the surface of thermal transmission member 3 where the first groove and the second groove are formed is formed into a convex surface, it is possible to discharge an excessive amount of the cooling fluid by gravitational force.

FIG. 11 is a schematic sectional view of a second cooler in the present embodiment. The second cooler in the present embodiment is provided with a thermal transmission member 4. Thermal transmission member 4 has a first groove 4 a. In thermal transmission member 4, a surface where first groove 4 a and a second groove are formed is formed into a convex surface. In thermal transmission member 4, a surface at the time of cutting by a surface along an extending direction of first groove 4 a is formed in a substantially arc shape.

First groove 4 a is formed to reach end surfaces of thermal transmission member 4. The second groove (not shown) is formed to reach the end surfaces of thermal transmission member 4. In thermal transmission member 4, a surface at the time of cutting by a surface along an extending direction of the second groove is formed into a substantially arc shape. Spray 11 is arranged right above a thickest part of thermal transmission member 4.

In the second cooler in the present embodiment, it is also possible to discharge an excessive amount of cooling fluid 21 towards the outside by the gravitational force as shown by an arrow 33.

In the thermal transmission member in the present embodiment, the surface in the extending direction of the first groove and the extending direction of the second groove is formed into a convex surface. However, the present embodiment is not limited to this mode but a section in one direction of the extending direction of the first groove and the extending direction of the second groove may be formed into a convex shape.

The other configurations, an operation and an effect are the same as the first embodiment and a description thereof will not be repeated.

Fourth Embodiment

With reference to FIGS. 12 and 13, a cooler in a fourth embodiment based on the present invention will be described.

FIG. 12 is a schematic plan view of a thermal transmission of the cooler in the present embodiment. The cooler in the present embodiment is provided with a thermal transmission member 5. Thermal transmission member 5 is formed in a plate shape. In thermal transmission member 5, a plan is formed into a substantially circular shape.

A first groove 5 a serving as the first channel and a second groove 5 b serving as the second channel are formed on a surface of thermal transmission member 5 to be sprayed with the cooling fluid. First groove 5 a and second groove 5 b are respectively formed into a linear shape. First groove 5 a and second groove 5 b are formed to intersect with each other.

There are formed a plurality of first grooves 5 a. First grooves 5 a are formed apart from each other so that a clearance between first grooves 5 a is at a substantially equal interval. There are arranged a plurality of second grooves 5 b. Second grooves 5 b are formed apart from each other so that a clearance between second grooves 5 b is at substantially equal interval.

Thermal transmission member 5 in the present embodiment has discharge groove 5 c and 5 d formed to surround an area where first groove 5 a and second groove 5 b are formed.

Discharge groove 5 c is formed to communicate with first groove 5 a. Discharge groove 5 c is formed to extend in the direction substantially perpendicular to an extending direction of first groove 5 a. Discharge groove 5 c is arranged in both ends of first groove 5 a. Discharge groove 5 d is formed to communicate with second groove 5 b. Discharge groove 5 d is formed to extend in the direction substantially perpendicular to an extending direction of second groove 5 b. Discharge groove 5 d is arranged in both ends of second groove 5 b. Discharge groove 5 c and 5 d extend up to end surfaces of thermal transmission member 5. Discharge grooves 5 c and 5 d are formed to discharge the cooling fluid to the outside of thermal transmission member 5.

FIG. 13 is a schematic sectional view of the cooler in the present embodiment. FIG. 13 is an arrow sectional view by the line XIII-XIII in FIG. 12. In discharge grooves 5 c and 5 d in the present embodiment, a section is formed into a U-letter shape.

In first groove 5 a in the present embodiment, depth is gradually deepened from a center part towards an outer peripheral part of the surface of thermal transmission member 1. That is, the surface of thermal transmission member 1 is formed in a plan shape and first groove 5 a is gradually deepened towards discharge groove 5 c. As well as first groove 5 a, second groove 5 b is formed to be gradually deepened towards discharge groove 5 d.

The cooling fluid is sprayed from spray 11 towards thermal transmission member 5. In the present embodiment, the cooling fluid sprayed to first groove 5 a is carried towards discharge groove 5 c as shown by an arrow 36. An excessive amount of the cooling fluid in first groove 5 a is guided to discharge groove 5 c. In such a way, since the depth is gradually deepened from the center part to the outer peripheral part, it is possible to actively discharge the excessive amount of the cooling fluid. With reference to FIG. 12, the excessive amount of the cooling fluid carried into discharge groove 5 c is discharged from thermal transmission member 5 as shown by an arrow 34.

In second groove 5 b, the excessive amount of the cooling fluid is guided to discharge groove 5 d. The excessive amount of the cooling fluid carried into discharge groove 5 d is discharged from thermal transmission member 5 as shown by an arrow 35.

In the present embodiment, the first groove and the second groove are formed to be gradually deepened towards the outside of the thermal transmission member. However, the present embodiment is not limited to this mode but one groove of the first groove and the second groove may be formed to be gradually deepened from the center part towards a peripheral part of the surface of the thermal transmission member.

The other configurations, an operation and an effect are the same as the first embodiment and a description thereof will not be repeated.

In the above drawings, the same or corresponding parts are given the same reference numerals.

It should be noted that the embodiments disclosed here are not restrictive but an example in all respects. A scope of the present invention is not shown by the above description but claims. The present invention should include all variations within similar meanings and ranges to the claims.

INDUSTRIAL APPLICABILITY

The present invention can be applied to a cooler for cooling a semiconductor element constituting an electric device (PCU: Power Control Unit) for controlling a rotating electric machine that drives a hybrid vehicle or the like. 

1. A cooler comprising: a thermal transmission member having a surface to be sprayed with a cooling fluid, wherein said thermal transmission member includes: a first channel formed on said surface; a second channel intersecting with said first channel (1 a-5 a), the second channel being formed on said surface, said first channel is formed to extend from one end surface of said thermal transmission member to another end surface, said second channel is formed so that ends of said second channel are arranged in an area inside a main surface of said thermal transmission member, each of said first channel and said second channel are formed into a groove shape so that said first and second channels have bottom surfaces respectively, and the bottom surface of said second channel is formed to be lower than the bottom surface of said first channel.
 2. The cooler according to claim 1, wherein said first channel is formed to supply said cooling fluid to a substantially entire part of said surface, said first channel is formed to discharge an excessive amount of said cooling fluid, and said second channel is formed to facilitate evaporation of said cooling fluid.
 3. The cooler according to claim 1, wherein in said second channel, a section perpendicular to an extending direction of said second channel is formed into a stepwise shape.
 4. The cooler according to claim 1, wherein in said thermal transmission member, said surface is formed into a convex surface so that a height is gradually reduced from a center part to an outer peripheral part.
 5. The cooler according to claim 1, wherein in said thermal transmission member, said surface is inclined so that a height is gradually reduced from a center part to an outer peripheral part.
 6. The cooler according to claim 1, wherein each of said first channel and said second channel is formed into a groove shape, and at least one channel of said first channel and said second channel is formed to be gradually deepened from a center part to an outer peripheral part of said surface.
 7. The cooler according to claim 1, wherein said second channel is formed into a groove shape, and said second channel is formed so that at least a part of said second channel generates a capillary phenomenon.
 8. (canceled) 